The invention relates to a method and an apparatus for monitoring a drive unit of a vehicle and/or components allocated thereto.
In German Patent No. 43 04 779 (corresponding to U.S. Pat. No. 5,484,351), an apparatus is discussed for controlling the torque emitted by a drive unit of a vehicle. In this context, means are provided that calculate the setting of the power parameters of the drive unit that is necessary for providing the torque; a correction is provided dependent at least on the torque requirement of auxiliary systems, as well as on engine torque losses. Here, it is provided that the program maps in which the torque requirement is stored are additively determined.
Furthermore, methods and apparatuses have been used for monitoring internal combustion engines. For this purpose, sensors have been used that detect operating characteristics. Such monitoring devices are very expensive, because as a rule additional sensors are required.
According to an exemplary embodiment of the present invention, faults of the internal combustion engine and/or of the allocated components may be recognized on the basis of a variable that characterizes the torque requirement of the drive unit and/or allocated components. In this context, faults may be recognized on the basis of the torque variable and/or a variable on the basis of which the torque variable may be determined. In particular, it is provided that the torque variables may be adapted. Here, faults may be recognized on the basis of the variables used for the adaptation and/or on the basis of the adapted variables.
According to an exemplary embodiment of the present invention, in certain operating states an operating characteristic may be controlled to a target value, the controller having at least integral behavior. This may be preferably a controlling of the idle speed.
This may mean that in particular operating states, such as, for example, idling, it may be monitored whether the actual drag torquexe2x80x94i.e., the instantaneous output torque of the idle controllerxe2x80x94agrees with the expected drag torque. This may be the case if the output signal of the idle controller is almost equal to an expected value. In this context, the expected value may be stored in a program map, preferably dependent on operating characteristics such as, for example, engine speed and a temperature variable.
If the drag torque does not agree, the stipulation of the drag torque may be corrected. On the basis of the variables used during the adaptation, such as the output signal of the idle controller, the deviation of the output signal of the idle controller from a comparison value, the value with which the drag torque may be corrected, and/or the drag torque, faults may be recognized when defined limits are exceeded.